A. Field of the Invention
The present invention relates to systems and methods for determining the dimensions of an object.
B. Description of Related Art
In systems that operate on large numbers of objects, it has been known to use imaging devices connected to a computer systems to automatically determine the characteristics of the objects. Uses of such systems include quality assurance visual inspection systems. In the manufacturing industry such systems are utilized to detect defects in the items being produced. The use of the automated defect detection systems compares the products being scanned against the desired characteristics to determine if the items being produced fall within allowable tolerances.
Another industry where such automated object characterization systems have become known is the package shipping industry. Packages are provided, for example, with bar codes, wherein various types of bar code scanners are used to read the bar code applied to a parcel. By decoding the information provided in the bar code, a computer connected to the bar code reader can determine, for example, the address to which the parcel is to be shipped. Such information can be used, for example, to route the package to the proper destination.
System have also been used to determine the dimensional weight of packages being shipped. Traditionally, shipping charges were determined based on the weight of a package handled by a shipper. The determination of shipping rates based solely on weight, however, leads to inefficiencies where, for example, the shipping charge for a large package containing lightweight articles fails to compensate the shipper for the volume taken by the package. By determining the dimensions of objects, shippers can allocate space more efficiently and charge rates that more accurately reflect the resources used. A number of systems have been used to automatically determine the dimensions of packages being shipped. Patent Cooperation Treaty No. WO99/49411 teaches the use of two light showers (linear arrays of sight sources opposed by linear arrays of light sensors) placed perpendicularly. The package dimensions are determined by analyzing the portion of each light shower that is blocked by the package. U.S. Pat. No. 5,815,274 for VOLUMETRIC MEASUREMENT OF A PARCEL USING A CCD LINE SCANNER AND HEIGHT SENSOR issued Feb. 17, 1998 to Reynolds et al. discloses a method of dimensioning using a linear CCD scanner positioned over a conveyor belt to determine the width and length of a parcel and a height scanner positioned adjacent to the belt to determine the height of the parcel. The height sensor projects light toward the parcel and receives light not blocked by the parcel at the other side to determine the height.